Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 2–3
Recent Avalanches: The avalanche activity on Seattle Ridge has continued, with a large avalanche on the Seattle Creek Headwall seen yesterday. It is unclear whether this avalanche was natural or human-triggered. Three days ago there were several human triggered avalanches on Seattle Ridge that failed on buried surface hoar, one of them intentionally triggered by cornice fall, and three triggered remotely at the same time by a person. There were also multiple natural avalanches observed from Taylor Pass.
Avlanche danger is expected to rise today through tonight as another round of snow and wind impacts the area. This system is looking to favor Turnagain Pass, and will likely bring 6 to 12" across the area. Given the current dangerous snowpack we have already been dealing with, this is cause for concern. The likelihood of natural and human triggered avalanches is increasing today, and very dangerous conditions are expected as the storm picks up.
We are expecting to see natural activity within the new snow (see Problem 2 for more), but the bigger concern is the layer of surface hoar buried 2 to 3' deep. We have seen large avalanches triggered on this area consistently over the past two weeks, and the new and windblown snow will be adding stress and making conditions even more touchy. In many cases avalanches have been triggered remotely, from low angle terrain adjacent to steeper slopes. Our current baseline is already dangerous, and that will get worse this afternoon into tonight. If you plan on getting out today, it will be important to enter the backcountry with a conservative mindset, and be ready to avoid avalanche terrain entirely as the weather picks up through the day.
New snow and strong winds will make cornice falls very likely today. These often trigger larger avalanches, especially with the kind of snowpack we are dealing with. Avoid lingering under cornices, and give them plenty of space if you are traveling along ridgelines.
Glide Avalanches remain likely, with at least two avalanches seen over the past week. These are very large and unpredictable. The only way to manage this problem is to avoid traveling below open glide cracks.
(3/8/2025)
Recent avalanche on the Seattle Creek Headwall, seen yesterday from Eddie's ridge.
Photo: Andy Moderow